1. Field of the Invention
The present invention relates to apparatus for the surveying of railroad track, and more particularly, although not exclusively, apparatus for assessing track health based on inspection.
2. Description of Related Art
Railroad tracks, also known as ‘permanent way’, consist of rails, fasteners, sleepers (ties), ballast and the underlying subgrade. A wide variety of variations are possible in terms of types of rail used, jointed or continuous welded, use of sleepers with ballast or slab track, type of fastenings used, and switch layouts. A number of associated track assets are also mounted on conventional railroad, such as equipment of signaling, lubrication, cabling and/or switch operation, amongst others. Over time, track components and assets degrade and endure damage because of the physical stress caused by movement of trains, changes in weather conditions causing compression or expansion in materials, rain and environmental conditions, and degradation in material strength with age.
Railroad track inspection processes are aimed at finding missing and defective components so as to be able to carry out effective maintenance with the intent of repair or replacement. If the track and associated assets are not monitored effectively, then there is a risk of complete failure or degradation to the extent that a significant risk is posed to safe operation of the railroad.
Human track inspectors have conventionally carried out the job of visual track inspection by walking along the railway track and taking notes on track condition which is later used to guide track maintenance activities. Such form of inspection is costly, unsafe, slow and prone to human error. Growth in rail networks, coupled with the time required for manual inspection has made it difficult in practice to carry out manual track inspection at the required inspection frequency with full network coverage.
Over the last two decades, rail infrastructure operators have increasingly started to carry out track monitoring using dedicated “inspection trains”. These trains are designed for hosting equipment for semi or fully automated track inspection equipment. Currently available systems of this kind use scanning equipment, including cameras and/or laser scanners, for monitoring various parts of the track. Implementation of the systems on inspection trains results in the various system components being distributed over a local network for the system, with sensing equipment being typically mounted on the vehicle exterior and data storage and control systems being mounted with a cabin interior, e.g. within suitable racks.
The implementation and maintenance of such systems is costly, and time consuming. In particular, such systems need extensive configuration to fit to a given vehicle which increases the complexity of installation and future maintenance burden. Each inspection train thus requires customisation such that it is fit for purpose. The overall distributed architecture comprising hardware components both outside and inside the vehicle, high power consumption, and the permanent equipment fixtures arrangement means that inspection trains have developed with time as their own subtype of railway vehicle.
However the cost of running inspection trains is burdensome. Not only due to the aforementioned installation and maintenance costs, but also because of the need to schedule inspection train journeys along busy railway lines. The running of inspection trains is to the potential detriment of the railway line capacity for passenger or freight vehicles, particularly considering the relatively low speeds at which conventional inspection trains gather data.
The data produced by the track scanning process may be transferred to an off-site computer network, where it can be analysed. The requirement for data to be amassed and communicated to a central location for processing, coupled with the detailed processing of the recorded data, can lead to a significant delay between the inspection itself and the deduction of any action required based on the inspection. Furthermore it can be problematic handling the large volumes of scan data generated.
It is an object of the present invention to provide a railroad track surveying system that overcomes or substantially mitigates one or more of the above disadvantages associated with the prior art. It may be considered an additional or alternative aim of the invention to provide a system that can provide useful track inspection results in a more convenient manner.
Although great strides have been made, considerable shortcomings remain.